Wednesday, November 12, 2008

The most accurate NBA Power Ranking on the web... and it has some shocking results

I have completed my first new and improved "Point Value over Average" NBA Power Ranking. PVOA is now adjusted for home and road efficiency, which are historically significant in the sport of basketball. Having done that, I truly believe I have achieved the basketball equivalent of the "DVOA" rankings on FootballOutsiders. I don't know what other factors I can adjust for. I think it provides for every exigency in the game of basketball. Thus if you want an objective assessment of how each NBA team is performing at any given moment, you can't do better than PVOA.

First of all, let me say this flatly: subjective opinion plays no role in the rankings. PVOA rankings only consider a team's performance against the NBA average. It takes no account of a team's future potential or what it did last season or its psychological state or any of that other bullshit. PVOA is about the numbers.

Here's how it works: Lets say the Chicago Bulls are playing the Boston Celtics in Boston. For the Bulls "PVOA" I consider how they performed in the game "per possession". I then compare that against the average "per possession" performance of all of the other opponents who have played against the Celtics in Boston.

For instance, lets say there were 92 possessions in the game. Lets further say that the Association was averaging 89 points in that many possessions and the Bulls scored 94. That would mean the Bulls outperformed the NBA average by 5, thus I would record a +5 in the Bulls offensive category. Now lets say on defense the Celtics scored 99 points, whereas they had been averaging against the rest of the Association's defenses... over 92 homecourt possessions... 90 points. That would be a defensive PVOA of +9 (plus is bad on defense), meaning the Bulls would end up with an overall PVOA total for that game of -4.

I then take all of the offensive and defensive totals from all the games, add them seperately and average them for the team's offensive and defensive averages, then add them together and rank all of the NBA teams accordingly.

Why I like it

Basketball is about possessions and points. How good is the team at converting possessions into points and preventing their opponent from doing the same. Ultimately, then, after a full season, you can compare the strength of each team by its "Efficiency Differential"... the difference between the number of points per 100 possessions versus the number of points allowed per 100 possessions.

But what if you want to assess a team DURING the season? Efficiency differential is inadequate because of the varying strength of each team's schedule.

PVOA accounts for that. Instead of considering how each team performed against their given opponent, PVOA asks how each team performed against the Association's performance against their givenopponent. In other words its schedule neutral.

But PVOA isn't perfect. In the first couple of weeks, when the sample size is small, we may get some deceptive results. But, by Christmas, I think PVOA will be able to tell us which teams are likely to advance in the playoffs. Last Christmas, my PVOA had all four of the NBA semifinalists... Boston, Detroit, Los Angeles, and San Antonio... and this was at a time when LA was 27-19, and most pundits questioned whether the Celtics could get through the Eastern Conference.

THE SHOCKING RESULTS

1 First, as my last post suggested, the Lakers look like an absolutely dominant team. They're number one in defense!! Historically, whenever the Lakers combine defense with their "Showtime" offense, they can't be stopped.

2. The Hawks are for real. How did they build that power so quickly... especially given their loss of the high Win Producer Josh Childress? I'm going to have to do a "Total Win Contribution" chart to find an explanation... similar to the one I did for the Timberwolves.

3. I thought the Pacers would be improved but thus far they are way up. I know Mike Dunleavy provides excellent offense, but the Pacers have a nice defensive thing going and I wonder if they wouln't want him to spoil the soup.

4. What the fuck are the Magic and Mavericks doing near the bottom? Both team's have huge Win Producers on their rosters, yet they seem to be cadillacing the start of the season.

5. My rankings suggest the Detroit title window is closing fast. I would argue with anyone who claimed Allen Iverson was a better point guard than Chauncey Billups. I suspect Dumars knows that. I think he was more concerned with blowing the team up, freeing its payroll, and possibly landing some new talent using the Billups savings.

6. The Heat are rising up again, and could challenge Atlanta and Indiana in the East. Dwayne Wade's having a great comeback season, and, as I suggested, Mario Chalmers is turning into a stud point guard. He plays excellent defense. And don't forget about Shawn Marion. He is a terrific Win Producer as well.